Sunday, 6 August 2006

Bet you haven't seen this one before

I told you that new species were two a penny in Australia. Here's an undescribed species of camaenid from central Australia. I collected material ages ago and never quite got round to naming it. Not good form, is it?

Camaenidae are surprisingly diverse and abundant in the Centre. They occupy two major habitats—crevices in rocks and around fig roots (that's one) and sand under spinifex (the other). This species is obviously a rock dweller. This isn't actually the rock on which is dwells (because I can't lay my hands on that slide right now) but it's not far away. The rock outcrop is probably its entire range. Luckily, it's within a national park.

In Australia, many of the rock dwellers are narrow range endemics. They're marooned on sandstone islands in a sea of inhospitable sand. They're stuck where they are—with few opportunities to broaden their ranges. Some species are restricted to a single gorge in the MacDonnell Ranges. Others, like this one, to a pile of rock.

The spinifex snails, on the other hand, have wide distributions. All that sand for them to crawl through. I'm surprised they haven't taken over the whole country. Interestingly, despite their extensive range, those genera—Pleuroxia and Sinumelon—haven't made it into south western Western Australia. In fact, none of the Camaenidae have. It's an odd biogeographical question. Anyone game to give us the answer?

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